Demand side management in mixed residential/commercial buildings with PV on site generation

Buildings with mixed residential and commercial units show relevant power peak that re further enhanced by shifting to electric source of nowadays gas-driven systems. The proposed solution is to organize a microgrid for such kind of buildings, aggregating different users with a common electric distribution system with a unique connection to the grid, a local common generation and a common heating/cooling system (electric-driven). This approach upgrades a group of independent several small users with rigid loads and chaotic behavior, to a large user with a flexible and controlled profile. A central building automation control system (BACS) managing all built-in technical systems and smart appliances may control load minute by minute, shifting in time plannable and controllable ones merging different kinds of load, obtaining a flatter diagram. The authors consider the suggested approach convenient to realize demand side management (DSM) for residential/commercial buildings. DSM exploits the flexibility of smart appliances and the thermal inertia of the structure, by imposing local and central set-points of heating and cooling systems according to the actual global net load and generation at a given moment. In the present paper, main aspects of the proposed control system are presented and simulations for a given case study with local PV generation are provided. Results show that this approach may lead to power peak reduction up to 20% even in the unfavorable case of combining commercial and residential units. Moreover, full self-consumption of locally generated energy from RES may be achieved.